Final answer:
Children typically begin to combine words around 18 months of age. This marks a significant cognitive milestone in language development, which progresses rapidly from single-word utterances to the ability to speak in short sentences by the age of three. The correct option is C.
Step-by-step explanation:
Children in all cultures begin to combine words around 18 months of age.
Cognitive Development Milestones
During the first few years of life, infants and toddlers experience significant cognitive development. Around 12 months, many infants may say their first words and can understand simple commands. As they approach 18 months, it is a major milestone where children start to combine words, reflecting their growing language skills and cognitive abilities.
By the age of two, a child's vocabulary may grow to as many as 50 words, and by the age of three, they can typically use short sentences and ask questions indicative of a rapid vocabulary expansion.
Understanding these milestones can provide important insights into the cognitive and language development stages common across different sociocultural contexts.